GraphQL API in a nutshell.

1. What is GraphQL API.

GraphQL was initially developed by Facebook in 2012 and later on Open sourced in 2015. It is a query language for API and a runtime for executing the Queries by using a type system defined for the data.

1. Key aspects of the GraphQL include.

   • Declarative Data fetching.

This means that clients can request the exact data that they need and nothing more. This is among GraphQL's pillar functionalities. It prevents over-fetching or under-fetching of data, improving efficiency.

• Single EndPoint.

Unlike REST, which may require multiple endpoints for different resources, GraphQL uses a single endpoint for all queries and mutations.

• Strongly Typed.

GraphQL API's have a strong type system defined using a schema. The schema serves as a contract between the client and the server, ensuring consistency.

• Real-time data.

Graphql can be used for real-time applications by utilizing subscriptions. Subscriptions allow clients to receive updates when the underlying data changes.

• GraphQL Schema.

At it's core, GraphQL has a schema. This defines the types of data that can be queried and the operations that can be performed.

A GraphQL Schema consists of:

• Types.

These represent the data structures in the API, like User, Product, or Post.

• Queries.

These are entry points for fetching data.Clients use queries to request specific data from the server.

• Mutations.

Entry points for modifying data. Clients use mutations to create, update, delete data.

• Subscriptions.

These are used for real-time updates. Clients can subscribe to changes in the data.

1. GraphQL servers.

To implement GraphQL API, one needs a server that understands GraphQL queries, resolves them, and returns the requested data.

Popular options for building GraphQL servers include:

a. Apollo Servers.

A widely used GraphQL server library for Node.Js.

b. Express-GraphQL.

This is the middleware for adding GraphQL to Express.js applications.

c. Graphene-Django.

This is the Python Library for building GraphQL APIs with Django.

d. GraphQL clients.

Clients use GraphQL to request data from the Server.

1. Popular GraphQL libraries include:

• Apollo client.

This is a JavaScript Library that is used for making GraphQL queries and mutations in Web and Mobile applications.

• Relay.

This is a JavaScript framework for building efficient and scalable GraphQL powered applications.

1. Use cases for GraphQL.

GraphQL is well suited for a variety of use cases:

a. Mobile applications.

GraphQL's flexibility allows mobile apps to request only the data they need, saving bandwidth and improving performance.

b. Real-time applications.

With subscriptions, GraphQL is suitable for Chat apps, live feeds, and other real-time systems.

c. Aggregating data.

GraphQL can serve as a single point of access to aggregate data from multiple sources.

d. Complex Queries.

For applications requiring complex queries with various filters, GraphQL simplifies the data-fetching process.

e. Microservices.

GraphQL can act as a facade for multiple MicroServices, providing a unified API to Clients.

f. Prototyping.

It is a great choice for rapid prototyping since you can quickly adapt the API to changing requirements.

1. Basic GraphQL query.

query {

user(id:1){

name

email

}

}

1. Basic GraphQL Mutation.

mutation{

createUser(input:{name:"John Doe", email:"john@example.com"}){

id

name

email

}

}

Thank you and see you in the next.

Special credits to @ainasanghi on X(Formerly Twitter).